Abstract
Purpose :
Emerging evidence indicates that histone deacetylase (HDAC) inhibitors have substantial efficacy in treating some types of cancer. Their direct effects and underlying molecular mechanisms on uveal melanoma, however, are largely unknown. In the present study, we determined if suberoylanilide hydroxamic acid (SAHA), the first HDAC inhibitor approved by the FDA for cancer therapy, alters uveal melanoma cell proliferation, migration, and apoptosis through modifying the acetylation status at the promoter of p21 gene.
Methods :
The concentration dependent effects of SAHA were determined on cultured M23 and SP6.5 uveal melanoma cell lines. The MTS assay measured their cell proliferation. Flow cytometry analyzed cell cycle progression. Caspase 3/7 assays examined cell apoptosis. The Transwell assay evaluated cell migration. qRT-PCR and Western blot were used to analyze gene and protein expression levels, respectively. Chromatin immunoprecipitation (ChIP) combined with qRT-PCR were performed to detect the effect of SAHA on the histone acetylation status at the p21 gene promoter.
Results :
The 50% inhibitory concentration (IC50) of SAHA were 2.1 µM and 1.7 µM in proliferating M23 and SP6.5 cells after 48 hours treatment by the MTS assay, respectively. This HDAC inhibitor induced G1-cell cycle arrest and also inhibited cell migration. However, it had no obvious effects on cell apoptosis. SAHA treatment markedly upregulated one of the CDK inhibitors, p21, in these different uveal melanoma cell lines. ChIP followed qRT-PCR showed that increases in H4ac at the p21 promoter accompanied increases in CDK inhibitor p21 expression.
Conclusions :
These results show that SAHA induced inhibition of HDAC slows cell cycle progression through increasing H4ac at the p21 promoter which in turn upregulates p21 protein expression. The resulting inhibitory effects on melanoma cell proliferation and migration imply that SAHA may be developed as a potential agent in uveal melanoma treatment.
This is a 2020 ARVO Annual Meeting abstract.